Introduction to the Basics of Light-Emitting Diodes

Release Date:

2022-06-10

　 Light-emitting diode An introduction to the relevant knowledge.

　　

Light-emitting diode

 

　　I. The advantages of light-emitting diodes are as follows:

　　1. Small size: the very small chip is encapsulated in epoxy resin.

　　2. Low power consumption. Generally Light-emitting diode Its operating voltage is 2–3.6 V, and its operating current is 0.02–0.03 A, so its power consumption does not exceed 0.1 W.

　　3. Long service life: under appropriate current and voltage conditions, the service life can reach 100,000 hours.

　　4. High brightness and low heat generation: utilizing cold-light technology, its heat output is significantly lower than that of conventional lighting fixtures.

　　5. Robust and durable: the LEDs are fully encapsulated in epoxy resin, making them more robust than incandescent bulbs and fluorescent tubes. There are no loose components inside the lamp, so it is less prone to damage.

　　II. How to Eliminate Static Electricity on Light-Emitting Diodes

　　Light-emitting diodes are SSD semiconductor devices, and the ESD immunity of different chips varies. Therefore, during the assembly of semi-finished and finished products, users must strengthen electrostatic protection measures and effectively prevent the generation of static electricity as well as dissipate any accumulated static charge.

　　All instruments and equipment that come into contact with light-emitting diodes must be grounded, with a grounding AC impedance of less than 1.0 ohm. Therefore, personnel handling LEDs should wear antistatic clothing, an antistatic wrist strap, or antistatic gloves, and, whenever possible, touch only the plastic body of the LED during handling. LEDs must be packaged in antistatic component boxes using antistatic packaging materials, and the ambient relative humidity should be maintained at around 60% to prevent static buildup caused by excessively dry air.

　　III. Relationship Between LED Color and Current

　　of different colors Light-emitting diode The forward operating voltage differs. Typically, under constant-current conditions, the standard operating current is 20 mA:

　　1. The operating voltage for red, yellow-green, grass-green, yellow, orange, and amber LEDs ranges from 1.8 to 2.4 V;

　　2. Operating voltage for blue, teal, pink, purple, white, and other colors: between 2.8 V and 3.4 V.

　　According to customer requirements, the operating voltage of light-emitting diodes is gradually reduced from 0.1 to 0.2 V through spectral and color separation processes. In addition, compared with small incandescent bulbs and neon lights, light-emitting diodes offer numerous advantages, including low operating voltage, small operating current, excellent shock and vibration resistance, high reliability, long service life, and energy efficiency and environmental friendliness. Moreover, the luminous intensity can be adjusted by regulating the current.

　　In fact, the reverse breakdown voltage of a light-emitting diode is around 5 volts, and its forward I–V characteristic curve is very steep. During operation, the current through the LED should be regulated by a series current-limiting resistor. Compared with incandescent lamps or neon lamps, LEDs operate at much lower voltages—some as low as only a few volts—and require very small operating currents; some emit light at currents as low as a few tenths of a milliampere. In addition, LEDs exhibit excellent shock and vibration resistance and have a long service life. The intensity of the emitted light can be adjusted by varying the current passing through the device.

More information

What is a light-emitting diode?

Light-emitting diodes are commonly referred to as LED beads. They are used in a wide range of applications and can be seen on streets and in alleys everywhere. For example, traffic lights at intersections remind people to obey traffic rules; remote controls transmit or receive signals; they can be used to display images on ultra-large screens; and various streetlights provide warm illumination at night. Even everyday household appliances rely on their contributions.

What are the tips for selecting LED chips?

1. Brightness: LED brightness varies, and so does the price. LEDs used in LED lighting must comply with laser safety classification standards.

What factors influence the price differences of LED light beads?

LED chips are a well-known product in the LED industry; however, many people are less familiar with their pricing. What causes such wide variations in LED chip prices? Below, we will outline the factors that influence LED chip prices.

What is the light-emitting principle of LED chips?

An LED chip is a light-emitting diode, and an LED bulb is simply the common, colloquial term for an LED.

Are you familiar with full-color LED chip-on-board modules for side mounting?

The brightness of full-color LED surface-mount devices is closely related to the LED’s viewing angle. The narrower the viewing angle, the higher the brightness; moreover, differences in manufacturing processes can lead to significant variations in service life. For a 5-mm LED with a 180-degree viewing angle, the white-light luminous intensity is only a few hundred mcd, whereas for a 15-degree viewing-angle LED, the luminous intensity exceeds 10,000 mcd. When high-power LEDs are used outdoors, the brightness is even greater. Single-power LEDs include 1 W, 3 W, and 5 W models; some high-power LEDs can be combined to form a single high-power LED with output up to several hundred watts. Color temperature is independent of brightness, but brightness is directly related to the lumen value.

Key Considerations for Full-Color SMD LEDs on the Side

Side-view full-color LED chips, also known as surface-mount LEDs, are a type of simple lighting device. Their light-emitting principle is based on passing an electric current through a compound semiconductor; when electrons and holes recombine, the excess energy is released in the form of light, thereby producing illumination.